FortiClient VPN 7.2.2.0753 on Ubuntu 22.04.3 LTS Bytes Received 0 KB (on other platforms VPN works)

[ldrahnik]

FortiClient VPN for android works, using web interface works, Windows app (I have dual boot Linux/Windows) works but on Ubuntu 22.04.3 LTS installed .deb FortiClient VPN v7.2.2.0753 does not. I see connected (given token was accepted) but then I see Bytes Received 0 KB and endpoint which is on other platforms reachable on Ubuntu is not. I exported logs using Export logs but I do not know what to look for. I appreciate any help.

[AEK]

Can you share the logs?

[ldrahnik]

https://gist.github.com/ldrahnik/feddb8da334a2eb5520e24d77cfdd694

[AEK]

Can you disable IPv6 on your Ubuntu and try again?

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=1

This will disable IPv6 temporarily and your IPv6 will back again after reboot.

[ldrahnik]

https://gist.github.com/ldrahnik/48665084700dc3466c5641308e2d6d1b

[AEK]

You have this errors:

20240315 22:29:11.797 TZ=+0100 [sslvpn:DEBG] route:332 route -n add -net 10.126.0.6 netmask 255.255.255.255 gw 10.212.134.201 dev fctvpn850944e2
20240315 22:29:11.797 TZ=+0100 [sslvpn:DEBG] route:334 Failed to add route: addr 10.126.0.6 netmask 255.255.255.255 gw 10.212.134.201 dev fctvpn850944e2
20240315 22:29:11.797 TZ=+0100 [sslvpn:DEBG] route:332 route -n add -net 172.18.64.255 netmask 255.255.255.255 gw 10.212.134.201 dev fctvpn850944e2
20240315 22:29:11.797 TZ=+0100 [sslvpn:DEBG] route:334 Failed to add route: addr 172.18.64.255 netmask 255.255.255.255 gw 10.212.134.201 dev fctvpn850944e2

Something seems preventing the client to add VPN routes to your routing table. Can you try add those routes with superuser once tunnel is established?

[ldrahnik]

No manual changes:

$ ip r | grep 10.212.134.201 
10.126.0.6 via 10.212.134.201 dev fctvpn850944e2 scope link linkdown 
172.18.64.255 via 10.212.134.201 dev fctvpn850944e2 scope link linkdown

Adding:

$ sudo /sbin/ip route add 10.126.0.6 via 10.212.134.200
RTNETLINK answers: File exists
ldrahnik@Zenbook-UP5401EA:~$ echo $?
2

[ldrahnik]

I found that my hotspot created by phone with android had configured for mobile data: IPv4-only, so I changed that to: IPv4/IPv6 but it looks like it changed nothing and the problem with app for ubuntu persists. With previous settings IPv4-only other apps work (mobile app, windows app, website app). Logs from today's attempt with changed configuration to including IPv6 I uploaded here:  https://gist.github.com/ldrahnik/2b8d03e57e36fbdac9ca39f87729abbb.